Patient-mounted retraction

ABSTRACT

Patient-mounted retractors with varying configurations and/or features are provided, along with additional components for use therewith in provided patient-mounted retractor assemblies. Blade type and tube type patient-mounted retractors that may be re-positioned during the course of a procedure are provided in varying configurations and/or geometries suitable for varying procedures and/or patient anatomies. Applications of re-positionable patient-mounted retractor assemblies are particularly suitable for use in minimally invasive procedures, eliminating the need for table-mounted retraction assemblies and/or cannulas that restrict the operating environment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a continuation of patent application Ser. No. 12/784,051 filed on May 20, 2010 which claims priority to U.S. provisional patent application No. 61/179,924, filed May 20, 2009, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to surgery, and in particular relates to patient-mounted retraction apparatuses and associated surgical methods and procedures for using same.

BACKGROUND

Retractors and/or cannulas may be used to provide a surgeon with an access portal to a surgical site in a patient's body. Various minimally invasive procedures, including spinal procedures such as decompression, fusion, external fixation, and the like may be performed through such access portals.

The retractors and/or cannulas typically used in these procedures must often be secured in position within a surgical site via external devices mounted to the operating table, for example via an adjustable arm coupled to a table mounted retractor frame. The setup, deployment, positioning, and repositioning of these devices before and during surgery can be awkward and time-consuming. Furthermore, the arms, frames, and other components associated with these table mounted retraction devices typically crowd the area around the surgical site, thereby reducing the space a surgeon has in which to operate, limiting the flexibility the surgeon has in his choice of instrumentation and/or hardware to accomplish a procedure, and impeding intra-operative imaging.

SUMMARY

In accordance with one embodiment, a retractor body with an anchor receptacle disposed at its distal end is provided. The anchor receptacle carries a locking assembly that is configured to connect the retractor body onto a bone anchor. The bone anchor is configured to be driven into an underlying target location of a patient.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of embodiments of the application, will be better understood when read in conjunction with the appended drawings. For the purposes of illustrating the patient-mounted retraction systems and methods of the present application, there are shown in the drawings preferred embodiments. It should be understood, however, that the instant application is not limited to the precise arrangements and/or instrumentalities illustrated in the drawings, in which:

FIG. 1 is a perspective view of a blade type patient-mounted retractor assembly in accordance with an embodiment;

FIG. 2 is a cross sectional view of the blade type patient-mounted retractor assembly illustrated in FIG. 1;

FIG. 3 is an exploded assembly view of the blade type patient-mounted retractor assembly illustrated in FIG. 1, including a retractor body, a locking cap, an intermediate wedge, a collet, and a bone anchor;

FIG. 4 is a perspective view of the locking cap, the intermediate wedge, the collet, and the bone anchor illustrated in FIG. 3 in an assembled configuration;

FIG. 5 is a perspective view of the locking cap, the intermediate wedge, and the collet illustrated in FIG. 3, in an assembled configuration;

FIG. 6 is an exploded assembly view of the blade type patient-mounted retractor assembly similar to FIG. 3, but constructed in accordance with an alternative embodiment;

FIG. 7 is an exploded assembly view of a blade type patient-mounted retractor assembly constructed in accordance with an alternative embodiment, including a collet with an integrated locking cap;

FIG. 8 is a perspective view of a retractor system including two blade type patient-mounted retractor assemblies disposed in a surgical site in accordance with an embodiment;

FIG. 9 is another perspective view of the retractor system illustrated in FIG. 8;

FIG. 10 is a cross sectional view of a tube type patient-mounted retractor assembly in accordance with an embodiment;

FIG. 11 is a perspective view of a distal end of the tube type patient-mounted retractor illustrated in FIG. 10;

FIG. 12 is a perspective view of flexible skirting affixed to the distal end of the tube type patient-mounted retractor illustrated in FIG. 11;

FIG. 13 is an exploded assembly view of an anchor cartridge in accordance with an embodiment;

FIG. 14 is a perspective view of the anchor cartridge illustrated in FIG. 13 in an assembled configuration;

FIGS. 15A and 15B are perspective view of the distal end of the tube type patient-mounted retractor illustrated in FIG. 10 with the anchor cartridge disposed therein in extended and fully inserted configurations respectively;

FIG. 16 is a perspective view of a tube type patient-mounted retractor assembly disposed in a surgical site in accordance with an embodiment;

FIG. 17 is a perspective view of the tube type patient-mounted retractor assembly illustrated in FIG. 16;

FIG. 18 is another perspective view of the tube type patient-mounted retractor assembly illustrated in FIG. 16.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “top,” “bottom,” “upper,” and “lower” designate directions in the drawings to which reference is made. The words “inwardly,” “outwardly,” “distally,” and “proximally” refer to directions toward or away from the geometric center of the element being described and designated parts thereof. The words, “anterior”, “posterior”, “superior”, “inferior”, “lateral”, “medial”, “sagittal”, “axial”, “coronal,” “cranial,” “caudal” and related words and/or phrases designate preferred positions and orientations in the human body to which reference is made and are not meant to be limiting. The terminology intended to be non-limiting includes the above-listed words, derivatives thereof and words of similar import.

Described herein are patient-mounted retractor assemblies having varying configurations and/or features. Patient-mounted retractor assemblies may be used in surgical procedures, for example minimally invasive spinal surgeries. Applications of patient-mounted retractor assemblies can include, but are not limited to, discectomies, laminectomies, facetectomies, pedicle screw fixation, and the like. The retractors used in the various patient-mounted retractor assemblies described herein may be configured using any geometry appropriate for retracting tissue, musculature, and other anatomical features from a surgical site, thereby facilitating access within the surgical site, for example by a surgeon performing a procedure. Patient-mounted retractors may be re-positionable within a surgical site, for example along one or more axes, thus providing additional flexibility and utility to a surgeon working within a surgical site. Unless otherwise indicated, the patient-mounted retractors, assemblies, and the various components thereof can be manufactured from any suitable biocompatible material known in the art including but not limited to titanium, titanium alloy, such as TAN, stainless steel, reinforced plastics, elastomeric materials, and the like, or any combination thereof.

The patient-mounted retractors described herein may have various features that facilitate re-configurable access to a surgical site. For example, patient-mounted retractors may have channels formed therein that themselves create, or may be used in combination with complimentary features of other retractors to provide, surgical site access, for example in the form of an “access portal.” An access portal may comprise an exposed area within a surgical site configured such that a surgeon performing a procedure is provided with adequate visibility into a surgical site and to provide sufficient space for the deployment and/or utilization of any instrumentation required for the corresponding procedure. Example geometries described herein include “blade” type retractors, such as the retractors depicted in FIGS. 1 to 9, “tube” type, or cannulated, retractors such as the retractor depicted in FIGS. 10 to 18. However, it should be noted that these patient-mounted retractor geometries are merely examples, and the scope of the instant disclosure should not thereto. Alternative patient-mounted retractor geometries may be conceived of by those skilled in the art without straying from the spirit and scope of the instant disclosure.

Referring to FIGS. 1-3, an example embodiment of a patient-mounted retractor assembly 100 includes a blade type retractor 102, a mounting post 115 (e.g., a bone anchor 116) that can be connected to the retractor 102, and a locking assembly 400 comprising locking components such as a collet 128, an intermediate wedge 144, and a locking cap 138. As will become appreciated from the following description, the geometric characteristics of the blade type retractor 102 illustrated in FIGS. 1 to 9 provide an example of one design for a blade type patient-mounted retractor, but any alternative geometry may be used as appropriate. The blade type retractor 102 includes a retraction member in the form of a generally cylindrical retractor body 104 with a proximal end 104 a, a distal end 104 b opposite the proximal end, and an intermediate portion 104 c defined between the proximal and distal ends 104 a and 104 b. It should be that the generally cylindrical geometry of the body depicted in the illustrative embodiments is merely an example body geometry, and that any other body geometries and/or body shapes for the body 104 may be used as desired. The body 104 of the retractor 102 may further include one or more accessory attachment points that may be configured to releasably receive optional accessories, such as illumination devices, suction apparatus, and the like.

The intermediate portion 104 c may define an offset region 105 disposed between the proximal and distal ends 104 a and 104 b, respectively. For example, the proximal end 104 a is centrally disposed on a first axis A1 and the distal end 104 b is centrally disposed on a second axis A2 that is offset with respect to the first axis. In the example embodiment, the intermediate portion 104 c is centrally disposed on an axis A3 that is offset with respect to both axes A1 and A2, thereby defining an offset region 105 of the body 104 between and with respect to the proximal end 104 a and the distal end 104 b. The degree of offset between the axes A1 and A2 may be tailored according to the anticipated use of the retractor, for example in accordance with a particular surgical site location within a patient, in accordance with a particular patient size and/or anatomy, and the like. It should be noted that the degree of offset between axes A1 and A2 depicted in the example embodiment illustrated in FIGS. 1-3 is merely an example offset, and the scope of the instant disclosure should not be limited thereto. For example, in an alternative embodiment, axes A1 and A2 may be coincident (i.e., there may be no offset region). In another alternative embodiment, there may be more than one, or varying degrees of offset within the offset region 105 of the intermediate portion 104 c, defined along one or more additional axes. Furthermore, while the axes A1 and A2 are depicted as vertical and substantially parallel, and while axes A1, A2, and A3 are all defined within a single plane, it should be noted that axes A1 and A2 could be non-parallel with respect to each other, and/or defined within different planes in alternative embodiments, and the resulting patient-mounted retractor geometries would still be considered within the scope of the instant disclosure.

At least a portion of the body 104 of the blade type patient-mounted retractor 102 may be hollow and/or open. For instance, in the example embodiment depicted in FIGS. 1-3, the body 104 of the blade type retractor 102 is closed at the distal end 104 b, hollow and open in the intermediate portion 104 c, throughout the offset region 105, and hollow and open at the proximal end 104 a, defining a curved plate 111 with opposing lateral edges 117. In alternative embodiments, the body 104 of the retractor 102 may be solid between the proximal and distal ends 104 a and 104 b, respectively, may be solid and/or closed at the proximal end 104 a, may be solid and/or closed at the distal end 104 b, or any combination thereof.

The body 104 of the blade type patient-mounted retractor 102 may include an auxiliary retraction member in the form of a flange 112 including a flange body 113 that defines a proximal end 113 a, a distal end 113 b opposite the proximal end 113 a, and a lateral edge 113 c. In the example embodiment, the flange 112 extends outwardly from one of the lateral edges 117 between the proximal and distal ends 104 a and 104 b of the body 104. The flange 112 may extend outwardly from the body 104 in any direction as appropriate. For example, the flange 112 may extend tangentially from an outer perimeter of the body 104, may extend outwardly along a chord defined between two points on a circumference of the body 104, or in any other direction as appropriate. In the illustrative embodiment, the lateral edge 113 c has a vertical profile that is essentially parallel with axes A1 and A2. In alternative embodiments, the lateral edge may be defined along an axis offset with respect to axes A1, A2, and/or A3, may have one or more sections of curvature, may have cutouts therefrom, or any combination thereof.

The vertical contour of the flange 112, as defined by the plane of the flange 112, can conform to the shape of the body 104 between the proximal and distal ends 104 a and 104 b, or may be defined independently of the geometry of the body. In the example embodiment illustrated in FIGS. 1 to 3, the vertical contour of the flange 112 is essentially coplanar with the lateral edge 117 from which it extends. However, it should be noted the geometry of the flange 112 depicted in FIGS. 1 to 3 is merely an example, and the scope of the instant disclosure should not be limited thereto. For instance, the flange body 113 of the flange 112 can exhibit one or more sections having bends and/or areas of curvature formed along one or more axes and/or within one or more planes with respect to the body 104, areas of concavity and/or convexity, or any combination thereof. The geometry of the flange 112 may be determined in part in accordance with a particular surgical site location within a patient, in accordance with a particular patient size and/or anatomy, and the like. In alternative embodiments, the body 104 of the blade type patient-mounted retractor 102 may define more than one flange 112 (not shown). In such embodiments, the flanges 112 may be configured with similar or disparate geometries, vertical contours, etc., with respect to each other.

The flange 112 may have one or more tabs 114 extending from the flange body 113, and in particular extending distally from the distal end 113 b of the flange body 113. The tab 114 may be configured to aide in the retraction of flesh, musculature, and the like when the blade type retractor is positioned and mounted in a surgical site. For example, the tab 114 may be configured to flexibly conform to bony anatomy when the retractor 102 is inserted into a surgical site, and in conforming to the bony anatomy may perform a scooping action to retract material located in close proximity to the bony surface that might otherwise obstruct visibility into the surgical site. If more than one tab 114 is desired, a series of slots (not shown) may be formed within the tab 114 and/or the distal end 113 b of the flange body 113, thereby defining a plurality of tabs. If the material properties of the retractor body 104 and/or the flange 112 do not exhibit a desired level of flexibility, one or more sections of flexible skirting made of a suitably elastomeric material, may be affixed to the distal end 113 b of the flange body 113 in lieu of the tab 114. The shape and geometry of the tab 114 with respect to the flange 112 may be configured as appropriate, for example in accordance with a particular patient size and/or anatomy, and the like.

The body 104 of the blade type patient-mounted retractor 102 may define a channel 110. The channel 110 may be configured to provide access to a surgical site when the patient-mounted retractor is mounted to a patient. The channel 110 may be defined by the body 104, alone or in combination with additional retraction members of the retractor, such as the flange 112. In this regard, it can be said that the channel 110 is at least partially defined by the body 104. The channel 110 may define any suitable shape, geometry, length, etc. as desired. For instance, in the example embodiment illustrated in FIGS. 1-3, the channel 110 is defined longitudinally by the hollow portions of the body 104 between the opening at the proximal end 104 a of the body and the closed distal end 104 b, and outwardly along the surface of the flange 112. The channel 110 may be configured to provide visibility and instrument access to a surgical site when mounted to a patient, thereby creating an access portal 158 in the surgical site. A retractor system 300, including two or more blade type patient-mounted retractor assemblies 100, may be used to create access portals 158 of varying sizes and/or geometries, as depicted in FIGS. 8 and 9 and discussed in greater detail below.

The blade type patient-mounted retractor 102 may be mounted to a patient by connecting the body 104 of the retractor to a mounting post 115. The mounting post 115 may be any type of fastener suitable to be removably inserted into a patient at a surgical site, for example a bone anchor, a nail, a pedicle mounting post, and the like. In the example embodiment depicted in FIGS. 1 to 9, the mounting post 115 is a bone anchor 116. In preferred embodiments, the blade type retractor 102 and the mounting post 115 are configured to allow the retractor to be polyaxially rotated or positionable about the mounting post 115 when the retractor 102 is connected to the mounting post 115. Rotation of the retractor about the mounting post 115 can allow a surgeon to initially position, and subsequently reposition if necessary, the retractor 102 as needed in order to maximize its utility in the surgical site. In alternative embodiments, the retractor body 104 and the mounting post 115 may be rigidly fixed with respect to one another prior to insertion of the retractor 102 in a surgical site.

The retractor assembly 100 can further include a mounting member 103 that can connect the body 104 of the blade type patient-mounted retractor 102 to the bone anchor 116. The mounting member 103 can be affixed to and/or formed in the body 104. In the example embodiment illustrated in FIGS. 1 to 3, the mounting member 103 is an anchor receptacle 106. The anchor receptacle 106 includes a proximal end 106 a, and a distal end 106 b opposite the proximal end. The anchor receptacle 106 may be formed within the body 104, or otherwise affixed to the body 104. In the example embodiment depicted in FIGS. 1 to 3, the anchor receptacle 106 is defined by the distal end 104 b of the body 104. The anchor receptacle 106 may be configured in accordance with the type of mounting post 115 to which the blade type retractor 102 will connect. For example, the anchor receptacle 106 may define an aperture 108 therein, the aperture 108 configured to receive the head of the bone anchor 116. In alternative embodiments, the anchor receptacle 106 may have a bore (such as the bore 210 illustrated in FIG. 10) formed within the distal end 106 b, the bore configured to receive the anchor cartridge 212 discussed in more detail below with reference to the tube type patient-mounted retractor 202. Additional components of the retractor assembly 100 may also be disposed within the aperture 108 of the anchor receptacle, for example the components of the locking assembly 400.

In the example embodiment depicted in FIGS. 1-3, the distal end 106 b of the anchor receptacle 106 can be open and tapered or otherwise narrowed with respect to the proximal end 106 a, so as to define a socket 106 c at the distal end 106 b. The socket 106 c can be configured to retain a collet 128 as described in more detail below. Alternatively, the socket 106 c may be configured to retain a head 120 of the bone anchor 116. It should be noted that the anchor receptacle 106 can be disposed at the distal end 104 b of the body 104 merely as an example anchor receptacle location, and that the anchor receptacle 106 could be formed in and/or affixed to any other location on the body 104 as desired.

The bone anchor 116 includes a shaft 118 that defines longitudinally opposing proximal and distal ends 118 a and 118 b respectively, and a head 120 coupled to the proximal end 118 a of the shaft 118. Helical threads 118 c extend circumferentially around the shaft 118 along a substantial entirety of the shaft between the proximal and distal ends 118 a and 118 b, respectively. The helical threads 118 c are configured to engage underlying bone. In one embodiment, the threads 118 c may define an outer diameter that remains substantially constant between the proximal and distal ends. In alternative embodiments, the outer diameter defined by the threads 118 c may vary over the length of the shaft, such that the outer diameter at the proximal end 118 a is greater in magnitude than the outer diameter of the threads at the distal end 118 b, or such that the outer diameter at the proximal end 118 a is lesser in magnitude than the outer diameter of the threads at the distal end 118 b. The shaft 118 of the bone anchor 116 may be cannulated, such that the bone anchor 116 may receive a guide wire in order to direct the trajectory of the bone anchor 116 when it is driven into position within a patient.

The head 120 includes an annular body 122 that defines a proximal end 122 a, a distal end 122 b opposite the proximal end, and a curved outer surface 122 c. The annular body 122 may be defined in the shape of a segment of a sphere having a diameter or cross-sectional dimension that is greater at a location between the proximal and distal ends than at either of the proximal and distal ends 122 a and 122 b respectively. Defining the annular body 122 in the shape of a segment of a sphere allows polyaxial rotation about the head 120 of the bone anchor 116. It should be noted that the head 120 can assume any other suitable shape as desired. The distal end 122 b of the head is formed and/or coupled to the proximal end 118 a of the shaft, either directly or indirectly via neck 124. The head may have driving features 126 formed therein, for example at the proximal end 122 a, the driving features configured to engage with complimentary driving features of a driving instrument (not shown).

As mentioned above, in preferred embodiments, the retractor 102 can be polyaxially positionable about the mounting post 115 when the retractor 102 is connected to the mounting post 115. The retractor assembly 100 can include a locking assembly 400 that can be connected to the retractor body 104, for example disposed within the anchor receptacle 106. The locking assembly 400 can include a collet 128, a locking cap 138, and an intermediate wedge 144. When the blade type retractor 102 has been connected to a mounting post 115, for example bone anchor 116, and positioned as desired within the surgical site, the retractor body 104 can be positionally fixed with respect to the mounting post 115 by engaging the locking assembly 400 to a locked configuration.

The collet 128 includes an annular body 130 that defines a proximal end 130 a, a distal end 130 b opposite the proximal end, a concave inner surface 130 c, and an opposing convex outer surface 130 d. The annular body 130 can define the shape of a segment of a sphere, having a diameter or cross-sectional dimension that is greater at a location between the proximal and distal ends than at either of the proximal and distal ends 130 a and 130 b.

The concave inner surface 130 c may define a spherical shape that substantially matches the curved outer surface 122 c of the head 120 of the bone anchor 116, such that the concave inner surface 130 c will be engaged with the curved outer surface 122 c when the head 120 of the bone anchor 116 is received in the collet 128. The inner surface of the socket 106 c may be configured in the shape of a segment of a sphere with a spherical volume that is substantially the same as or slightly greater in magnitude than the spherical volume of the convex outside surface 130 d of the collet 128. The annular body 130 further includes a plurality of circumferentially spaced retention fingers 132 formed within the distal end 130 b of the annular body 130. The retention fingers 132 are configured such that circumferentially adjacent fingers 132 are separated by a slot 134 that extends proximally upwards into the body 130 from the distal end 130 b.

The retention fingers 132 are configured to retain the head 120 of the bone anchor 116. As the collet 128 is first disposed onto the head 120 of the bone anchor 116, the retention fingers 132 deflect, spreading outwardly from the center of the collet along the curved outer surface 122 c of the head 120. Once the tips at the distal ends of the fingers 132 move beyond the portion of the curved outer 122 c surface with the largest diameter between the proximal and distal ends 122 a and 122 b, the fingers 132 “snap” back to their original shape, thus releasably retaining the head 120 of the bone anchor within the collet 128 via a snap fit. The spherical inner surface of the socket 106 c is sufficiently sized to accommodate snapping the collet 128 into place over the head 120 of the bone anchor 116, and for removal of the bone anchor from the collet, while the collet and the bone anchor are disposed within the anchor receptacle 106.

The collet 128 may be retained in the aperture 108 of the anchor receptacle by a locking cap 138 and an intermediate wedge 144. The collet 128 includes an annular ring 136 formed at the proximal end 130 a of the annular body 130. The annular ring 136 is configured to engage the lower surface 146 b of the intermediate wedge 144 or the bottom surface of a locking cap 138, and to provide axial alignment of the collet within the aperture 108 of the anchor receptacle 106. The locking cap 138 includes a body 140 defining a proximal end 140 a, a distal end 140 b opposite the proximal end. Helical threads 140 c, configured to engage complimentary threads 106 d formed within the surface of the aperture 108 at the proximal end 106 a of the anchor receptacle 106, extend circumferentially around the body 140 along a substantial entirety of the body between the proximal and distal ends. The locking cap 138 may have driving features 142 formed therein, for example at the proximal end 140 a. The driving features 142 are configured to engage with complimentary driving features of a driving instrument (not shown). The locking cap 138 may have a longitudinal aperture 140 d formed therethrough. The aperture 140 d is configured to receive a raised collar 148 of the intermediate wedge 144. The locking cap 138 may be configured to be removable from the anchor receptacle 106, or alternatively may be configured to be captive within the anchor receptacle 106, and therefore non-removable.

The intermediate wedge 144 may be disposed within the aperture 108 of the anchor receptacle 106, at a location between the collet 128 and the locking cap 138. The intermediate wedge 144 includes a generally cylindrical shaped body 146 defining an upper surface 146 a at the proximal end of the body and an opposing lower surface 146 b at the distal end of the body. The body 146 further includes a raised collar 148 extending upwardly from the upper surface 146 a at the proximal end of the body 146, the collar configured to be received within the longitudinal aperture 140 d of the locking cap 138. A longitudinal aperture 150 may extend through the raised collar 148 and the body 146. The aperture 150 can have a diameter that is sufficiently large to allow a guide wire to pass through. The intermediate wedge 144 may have one or more raised ridges 152 formed on the outer surface of the body 146 between the proximal and distal ends 146 a and 146 b. The raised ridge 152 may be configured to slidably engage with a complimentary slot (not shown) formed in the surface of the aperture 108 of the anchor receptacle 106. The raised ridge 152, when received in slidable engagement with the complimentary slot in the anchor receptacle 106, prevents rotation of the intermediate wedge 144 within the aperture 108.

The lower surface 146 b of the body 146 may be configured as a relatively flat plane configured to engage with the annular ring 136 of collet 128. In accordance with an alternative embodiment, a collet 154 (as depicted in FIG. 6) replaces the collet 128 in the locking assembly 400, and the intermediate wedge 144 may be configured accordingly with a substantially concave lower surface 146 b configured to engage with the spherical upper surface of the collet 154, thereby providing an enhanced magnitude of surface area contact between the collet 154 and the intermediate wedge 144 with respect to the magnitude of surface area contact between the collet 128 and the intermediate wedge 144. Enhancing the magnitude of surface area contact between a collet and an intermediate wedge can result in a more robust interface between the locking components of the locking assembly 400 when the locking assembly 400 is activated to a locked configuration.

In an example method of using the blade type patient-mounted retractor 102, a mounting post 115, for example the bone anchor 116, is inserted into an underlying target location 107 of a patient at a surgical site. The target location 107 can be an underlying bone such as a vertebral body V1. In accordance with one embodiment, the target location 107 is a pedicle P1 of the vertebral body V1. The blade type retractor 102 may then be connected to the head of the bone anchor 116. The blade type retractor 102 may have the anchor receptacle 106 disposed at the distal end 104 b of the retractor. The anchor receptacle may have locking components disposed within it, for example a collet (e.g., collets 128 or 154), an intermediate wedge 144, and a locking cap 138. It should be noted that certain of these locking components of the locking assembly 400 may be omitted, as discussed in more detail below. To aide deployment of the blade type patient-mounted retractor, it may be desirable to first locate a desired insertion point for the bone anchor via the insertion of a guide wire. A cannulated version of the bone anchor 116 may then be inserted into the surgical site over the guide wire to guide the trajectory of the bone anchor 116 as it is driven into the desired surgical location. The guide wire may also be passed through the anchor receptacle 106 and the locking assembly 400 disposed therein, and used to guide the alignment of the collet with the head of the bone anchor.

The retractor 102 may be connected to the bone anchor 116 by snapping the collet 128 that is disposed in the anchor receptacle 106 over the head 120 of the bone anchor 116. When the retractor body 104 is connected to the head 120 of the bone anchor 116, the retractor 102 can be rotatably positionable about the head 120 of the bone anchor 116. Once the blade type retractor 102 has been positioned to provide the desired access portal 158 at the surgical site, the retractor body 104 may be fixed with respect to the bone anchor 116 by activating the locking assembly 400 to the locked configuration. Although a single blade type retractor 102 can be used to define an access portal 158, greater flexibility is achieved when two or more blade type retractors are deployed at a surgical site, as depicted in FIGS. 8 and 9. In FIGS. 8 and 9, a retractor system 300 including two blade type retractor assemblies 100 is mounted to respective target locations 107 that are spaced from each other at a surgical site, such that the respective retractors 102 oppose each other. In particular, the retractors 102 are positioned such that the respective channels 110 face each other so as to form the access portal 158 at the surgical site. The access portal 158 is re-configurable, for example during the course of a procedure, by releasing the locking assembly 400 of one or both of the retractor assemblies 100 to an unlocked configuration, repositioning one or both of the retractors 102 to reconfigure the access portal 158 as desired, then re-activating the locking assembly 400 of the respective retractor assembly 100 or assemblies 100 to the locked configuration, thereby securing the respective retractor 102 or retractors 102 in their new positions.

In one example of activating the locking assembly 400 of a blade type patient-mounted retractor 102, for example using the collet 128 or 154, the intermediate wedge 144, and the locking cap 138, a driving instrument may be inserted into the channel 110 of the corresponding retractor 102, and a rotational driving force applied to the locking cap 138, thereby advancing the locking cap 138 in a distal, or downward, direction within the anchor receptacle 106, toward the collet 128. If access to the channel 110 would be blocked by the geometry of the body 104 of the retractor 102, an instrument aperture 104 d may be formed within the body 104. The aperture 104 d can be configured to allow access by a driving instrument to the anchor receptacle 106. If an intermediate wedge 144 is disposed between the locking cap 138 and the collet 128, the advancing locking cap 138 will transfer downward force to the intermediate wedge 144, causing the intermediate wedge 144 to advance in a distal or downward direction within the anchor receptacle 106. As the intermediate wedge 144 advances, the lower surface 146 b of the wedge 144 makes contact with the proximal end of the collet 128, thereby transferring downward force to the collet 128 and causing the retention fingers 132 to interfere with the inner surface of the socket 106 c at the distal end 106 b of the anchor receptacle 106, and to collapse around the head 120 of the bone anchor 116, thereby fixing the anchor receptacle 106, and thus the retractor body 104, in position with respect to the head 120 of the bone anchor 116 via a crush lock between the collet 128 and the bone anchor 116.

If a surgeon performing a procedure desires to reposition the blade type patient-mounted retractor 102, a rotational driving force of the opposite direction to that applied during activation of the locking assembly 400 may be applied to release the locking assembly 400 to its unlocked configuration, thereby re-enabling polyaxial positioning of the retractor 102 with respect to the bone anchor 116. When the retractor 102 is repositioned as desired, the locking assembly 400 can be activated again to its locked configuration as described above to re-lock the retractor 102 in position with respect to the head 120 of the bone anchor 116. The blade type patient-mounted retractor 102 can be removed from the surgical site by releasing the locking assembly 400 and applying an upward force to the retractor body 104, thereby causing the collet 128 to disengage from the head 120 of the bone anchor 116. The bone anchor 116 may be removed from the surgical site, or may be re-used, for example as a bone anchoring element of a bottom-loading pedicle screw assembly. It should be noted that while the instant example method is discussed within reference to the use of solely blade type patient-mounted retractors, it is possible to use blade type patient-mounted retractors in conjunction with tube type patient-mounted retractors during a single procedure.

As described above, various embodiments of the locking assembly 400 may omit one or more of the locking components described above. For example, it is possible to omit the intermediate wedge 144 in certain embodiments. When the intermediate wedge 144 is omitted, the lower surface of the locking cap 138 makes direct contact with the collet 128 as the locking cap 138 is advanced in the anchor receptacle 106. In embodiments where the intermediate wedge 144 is so omitted, the upper surface of the collet 128 at the proximal end 130 a may have an engagement structure formed thereon, the engagement structure configured to engage the lower surface of the locking cap 138 as it is advanced, thereby transferring downward force from the locking cap 138 to the collet 128. The lower surface of the locking cap 138 may similarly include engagement structure formed thereon, the engagement structure configured to engage the upper surface of the collet 128 as the locking cap 138 is advanced. Alternatively, both the lower surface of the locking cap 138 and the upper surface of the collet 128 may have complimentary engagement structure formed thereon. In accordance with another alternative embodiment of the locking assembly 400, the locking cap 138 and the collet 128 can be combined into a unitary locking collet 156, depicted in FIG. 7.

It should be noted that although locking the retractor body 104 in position with respect to the bone anchor 116 has been discussed with reference to the locking assembly 400 disposed within the anchor receptacle 106, the scope of the instant disclosure should not be limited thereto. For instance, the retractor body 104 may alternatively be connected to the bone anchor 116 and/or locked in place with respect to the bone anchor 116 via alternatively constructed locking assemblies. For example, the curved outer surface 122 c of the head 120 of the bone anchor 116 may have helical threads formed thereon, the threads configured to engage complimentary threads formed within the distal end 106 b of the anchor receptacle 106. Alternatively, the head 120 of the bone anchor 116 and the anchor receptacle 106 may have ball and detent features disposed therein, thereby providing predetermined angulation settings between the retractor body and the bone anchor and toolless adjustment. Of course any other components and/or mechanisms can be used to connect the blade type retractor to the bone anchor and/or lock the position of the retractor in position with respect to the bone anchor as desired.

Now referring to FIGS. 10-18, a patient-mounted retractor assembly 200 can be constructed in accordance with an embodiment. The retractor assembly 200 can include a tube type retractor 202, a mounting post 115, a locking assembly 500 configured to secure the mounting post 115 to the retractor 202, and an anchor cartridge 212 that is configured to provide axial translation of the retractor 202 with respect to the mounting post 115, and can carry components of the locking assembly 500. As will become appreciated from the following description, the body geometry characteristics of the tube type retractor 202 illustrated in FIGS. 10-18 provide an example of one design for a tube type patient-mounted retractor, but alternative body geometries may be used as appropriate. The tube type retractor 202 includes a generally tube shaped retractor body 204 defining a proximal end 204 a, a distal end 204 b opposite the proximal end, and an intermediate portion 204 c disposed between the proximal end 204 a and the distal end 204 b. The retractor 202 further includes at least one bore 206 formed through the body 204 along a longitudinal axis A4. The bore 206 defines a first opening 206 a at the proximal end 204 a of the body 204, a second opening 206 b disposed at the distal end 204 b of the body 204, and an intermediate section 206 c between the first opening 206 a and the second opening 206 b. The bore 206 may serve of similar use as the channel 110 and/or access portal 158 defined by the blade-type patient-mounted retractor 102, in that the bore 206 may provide visibility into a surgical site and space for the deployment and/or utilization of instrumentation to be used during a surgical procedure. In alternative embodiments, two or more bores 206 may be formed within the body 204 of the tube type retractor. The body 204 of the retractor 202 may further include one or more accessory attachment points that may be configured to releasably receive optional accessories, such as illumination devices, suction apparatus, and the like.

A cross sectional dimension of the bore can vary between the proximal and distal ends 206 a and 206 b, respectively. For example, the cross sectional dimension may be the diameter of the bore 206. In the illustrative environment, the first opening 206 a has a diameter of greater magnitude than the diameter of the second opening 206 b. The diameter of the bore 206 gradually decreases along the intermediate section 206 c from the first opening 206 a to the second opening 206 b. In an alternative embodiment the first opening 206 a may have a diameter of lesser magnitude than the diameter of the second opening 206 b, and the diameter of the bore 206 may gradually increase along the intermediate section 206 c from the first opening to the second opening. In another embodiment, the first and second openings 206 a and 206 b may have diameters of equal magnitude, and the diameter of the bore 206 may remain constant along the intermediate section 206 c. In another alternative embodiment, the diameter may vary along the intermediate section 206 c, regardless of the diameter of the first opening 206 a or the second opening 206 b. Of course other cross sectional dimensions, such as area, may be used to define the characteristics of the bore 206.

The distal end 204 b of the body 204 may have a profiled edge 204 d formed therein at a location proximate to the second opening 206 b. The geometry of the profiled edge 204 d may be defined at least in part in accordance with the intended use of the tube type retractor, for example in accordance with the underlying bony anatomy that the distal end 204 b of the retractor may engage in a surgical site. For example, the profiled edge 204 d can include one or more angled and/or curved cutout sections defined along the perimeter of the distal end 204 d of the body, the cutout sections configured to conform to bony structure or other patient anatomy at a surgical site.

The retractor 202 can include one or more tabs 214 extending distally from the distal end 204 b of the body 204, for example along the profiled edge 204 d, as illustrated in FIG. 11. The tabs 214 may be configured to aide in the retraction of flesh, musculature, and the like when the tube type retractor is positioned and mounted in a surgical site. For example, the tabs 214 may be configured to flexibly conform to bony anatomy when the retractor 202 is inserted into a surgical site, and in conforming to the bony anatomy may perform a scooping action to retract material located in close proximity to the bony surface that might otherwise obstruct visibility into the surgical site. The tabs 214 may be separated by a series of slots 216 extending from the distal end 204 b of the body 204 upward towards the proximal end 204 a. The number and length of the slots 216 may determine the flexibility, and thus the conforming characteristics, of the tabs 214. If the material properties of the retractor body 204 do not exhibit a desired level of flexibility, one or more sections of flexible skirting 218, made of a suitably elastomeric material, may be affixed to the distal end 204 b of body in lieu of the tabs 214, as illustrated in FIG. 12.

The tube type patient-mounted retractor 202 includes a generally circular bore 206 that extends through the body 204, and a straight intermediate section 204 c extending between the proximal and distal ends 204 a and 204 b of the body 204. It should be appreciated, however, that the shape of the bore 206 and the body 204 are merely example shapes, and the scope of the instant disclosure should not be limited thereto. Tube type patient-mounted retractors 202 with many variations of the above shapes are possible and are intended to be included within the scope of the instant disclosure. For example: the geometry of the bore 206 may be elliptical, square, rectangular, hexagonal, or any other shape; the geometry of the retractor body 204 may conform to the geometry of the bore, or the body 204 may have a different geometry from the bore (e.g., a circular bore through a square body); and the intermediate section 206 c of the bore 206 may have one or more areas of bends, steps, curvature, differing geometry, or other variations from straightness and/or uniformity of geometry. The geometric characteristics of the tube type retractor 202 may be determined in accordance with, for example, with a particular surgical site location within a patient, in accordance with a particular patient size and/or anatomy, and the like.

The retractor assembly 200 can include a mounting post 115 configured to connect to the tube type patient-mounted retractor 202, and in particular to the retractor body 204. The mounting post 115 may be inserted into a target location 109 of the patient at a surgical site so as to, in turn, mount the retractor 202 to the patient. The mounting post 115 may be provided as any type of fastener suitable to be removably inserted into a patient at a surgical site, for example a bone anchor, a nail, a pedicle mounting post, and the like. In accordance with the illustrated embodiment, the mounting post 115 is the bone anchor 116. In preferred embodiments, the tube type retractor 202 and the mounting post 115 are configured to allow the retractor 202 to be rotatable or polyaxially positionable about the mounting post 115 when the retractor 202 is connected to the mounting post 115. The rotatability of the retractor 202 to the mounting post 115 allows a surgeon to initially position, and subsequently reposition if necessary, the retractor 202 as needed in order to maximize its utility in the surgical site. In alternative embodiments, the retractor 202 and the mounting post 115 may be rigidly fixed with respect to one another prior to insertion in a surgical site.

The body 204 of the tube type patient-mounted retractor 202 can be connected to the bone anchor 116 utilizing a mounting member 203 affixed to and/or formed in the body 204. In accordance with the illustrated embodiment, the mounting member 203 is an anchor receptacle 208. The anchor receptacle 208 can be formed on the body 204 of the retractor 202 between the proximal and distal ends 204 a and 204 b, respectively, and adjacent to the bore 206. The anchor receptacle 208 includes a proximal end 208 a, and a distal end 208 b opposite the proximal end 208 a. A cylindrical bore 210 is formed in the distal end 208 b of the anchor receptacle 208. The bore 210 is configured to receive an anchor cartridge 212 discussed in more detail below. In alternative embodiments, the anchor receptacle 208 may have an aperture and/or a socket formed therein as described above with respect to the aperture 108 and socket 106 c formed in the anchor receptacle 106 of the blade type patient-mounted retractor 102. A locking assembly constructed as described above with respect to the locking assembly 400 of the blade type patient-mounted retractor 102 may be disposed in such an aperture.

The anchor receptacle 208 may be formed within the body 204, or otherwise affixed to the body. In accordance with the illustrated embodiment, the anchor receptacle 208 is formed at the distal end 204 b of the body 204, at a location adjacent to the bore 206. The cylindrical bore 210 is formed in the anchor receptacle 208 along an axis A5 that is offset from the longitudinal axis A4. The degree of offset between the axes A4 and A5 may be determined by the desired resulting geometry of the tube type retractor, for example in accordance with a particular surgical site location within a patient, in accordance with a particular patient size and/or anatomy, and the like. In order to provide access, for example by a driving instrument, to structures used in configuring and/or reconfiguring the position of the tube type retractor 202 in a surgical site, access channels 208 c and 208 d may be formed within the anchor receptacle 208. More or fewer access channels may be formed as necessary. Access channel 208 c can be defined by a longitudinal bore 209 a that extends distally along axis A5 from the first opening 206 a of the bore 206 and into the bore 210. Access channel 208 d can be defined by a longitudinal bore 209 b that extends between a bore opening 209 c, defined within the intermediate section 206 c of the bore 206 above an engagement member, and a distal end 209 d located below the engagement member. It should be noted that while the anchor receptacle 208 is disposed adjacent to the bore 206 at the distal end 204 b of the body 204 in accordance with the illustrated embodiment, the anchor receptacle 208 can alternatively be formed in and/or affixed to any other location on the body 204 as desired.

The anchor cartridge 212 is configured to be received in the bore 210 of the anchor receptacle 208. The anchor cartridge 212 includes a cartridge body 220 defining a proximal end 220 a, a distal end 220 b opposite the proximal end, and an outside surface 220 c. The anchor cartridge 212 can define an aperture 222 that extends through the body 220. Locking components of the locking assembly 500 or the locking assembly 400 can be disposed in the aperture 222 of the anchor cartridge 212. Helical threads 220 e, configured to engage complimentary threads 140 c of the locking cap 138, may be formed within the surface of the aperture 222 at the proximal end 220 a of the anchor cartridge 212. The distal end 220 b of the anchor cartridge 212 may be open and tapered or otherwise narrowed with respect to the proximal end 220 a, thereby defining a socket 220 d. In one embodiment, the socket 220 d is configured to retain a collet 232. Alternatively, the socket 220 d may be configured to retain the head 120 of the bone anchor 116.

The anchor cartridge 212 is configured to be axially translated within the bore 210 of the anchor receptacle 208. In a preferred embodiment, the outer surface 220 c of the anchor cartridge 212 has a series of annular ridges 224 formed thereon. The annular ridges 224 are configured to be engaged by an engagement member disposed within the bore 210 of the anchor receptacle 208, such as the pawl 226. The pawl 226 includes a base 228. The base can be configured to be received within the aperture 229 formed in the distal end 208 b of the anchor receptacle 208. The base 228 can be affixed to the anchor receptacle 208, for example by a fastener inserted through bore 228 a and received in the distal end 208 b of the anchor receptacle. The pawl 226 further includes an arm 230 defining a proximal end 230 a, a distal end 230 b opposite the proximal end 230 a, and an engagement member 230 c. The engagement member 230 c is configured to engage the annular ridges 224 formed on the outer surface 220 c of the anchor cartridge 212, so as to prevent the anchor cartridge from inadvertently backing out of the bore 210. The engagement member 230 c can have the shape of a tooth configured to engage an annular ridge 224, or any other shape as desired. The arm 230 also has a release tab 230 d disposed proximate to the proximal end 230 a. The release tab 230 d is configured to cause the arm 230, and thus the engagement member 230 c, to deflect away from the anchor cartridge 212 when a downward force is applied to the release tab 230 d.

In accordance with the example embodiment illustrated in FIGS. 10-15B, as the anchor cartridge 212 is inserted into the bore 210 in the distal end 208 b of the anchor receptacle 208, with the proximal end 220 a inserted first, the outer surface 220 c of the proximal end 220 a of the anchor cartridge 212 interferes with the engagement member 230 c on the arm 230 of the pawl 226, thereby causing the proximal end 230 a of the arm 230 to deflect outwardly, away from the anchor cartridge 212. As the anchor cartridge 212 is further inserted, the engagement member 230 c falls into the first of the annular ridges 224, and will snap back into its non-deflected state. At this point, the anchor cartridge 212 will be in an extended state, as depicted in FIG. 15A. The engagement member 230 c will hug the annular ridge 224 that it engages, thereby preventing the anchor cartridge 212 from inadvertently backing out of the bore 210. As the anchor cartridge 212 is advanced further into the bore 210, the engagement member 230 c rides up along each subsequent annular ridge 224, the proximal end 230 a of the arm deflecting outwardly away from the anchor cartridge 212, then snapping back into its non-deflected state as is passes by the apex of each successive annular ridge 224. Eventually the anchor cartridge 212 becomes fully inserted into the bore 210, as illustrated in FIG. 15B. It should be noted that the annular ridges 224 and complimentary pawl 226 are merely example implementations that facilitate the axial translation of the anchor cartridge, and the scope of the instant disclosure should not be limited thereto.

In preferred embodiments, the tube type retractor 202 and the mounting post 115 are configured to allow the retractor 202 to be rotatable or polyaxially positionable about the mounting post 115 when the retractor 202 is connected to the mounting post 115. When the tube type retractor 202 is connected to the mounting post 115, for example bone anchor 116, and positioned as desired within the surgical site, the retractor body 204 can be fixed with respect to the mounting post 115 by engaging the locking assembly 500 disposed in the aperture 222 of the anchor cartridge 212 to a locked configuration. In the example embodiment the locking assembly 500 includes the locking components depicted in FIGS. 10-14, including a collet 232, an intermediate wedge 244, the locking cap 138, and a peg 256 that rotatably secures the collet 232 and the intermediate wedge 244. In alternative embodiments, the locking assembly 500 can include locking components similar to those described above with respect to the locking assembly 400 that is disposed within the aperture 108 of the anchor receptacle 106. In particular, the locking assembly 500 can include a collet (e.g., collets 128, 154, 156, or 232), a locking cap 138 usable with select ones of the collets, an intermediate wedge (e.g., intermediate wedges 144 or 244), and the peg 256.

The collet 232 includes an annular body 234 that defines a proximal end 234 a, a distal end 234 b opposite the proximal end, a concave inner surface 234 c, and an opposing convex outer surface 234 d. The annular body 234 can define the shape of a segment of a sphere, having a diameter or cross-sectional dimension that is greater at a location between the proximal and distal ends than at either of the proximal and distal ends 234 a and 234 b. The collet 232 has a pair of notches 236 formed in the proximal end 234 a. The notches 236 are configured to engage complimentary tabs 252 formed on the lower surface 246 b of the intermediary wedge 244.

The concave inner surface 234 c may define a spherical shape that substantially matches the curved outer surface 122 c of the head 120 of the bone anchor 116, such that the concave inner surface 234 c engages the curved outer surface 122 c when the head 120 of the bone anchor 116 is received in the collet 232. The inner surface of the socket 220 d may be configured in the shape of a segment of a sphere with a spherical volume that is substantially the same as or slightly greater in magnitude than the spherical volume of the convex outside surface 234 d of the collet 232. The annular body 234 further includes a plurality of circumferentially spaced retention fingers 240 formed within the distal end 234 b of the annular body 234. The retention fingers 240 are configured such that circumferentially adjacent fingers are separated by a slot 242 that extends proximally upwards into the body 234 from the distal end 234 b.

The retention fingers 240 are configured to retain the head 120 of the bone anchor 116. As the collet 232 is first placed over the head 120 of the bone anchor 116, the retention fingers 240 deflect, spreading outwardly from the center of the collet 232 along the curved outer surface 122 c of the head 120. Once the tips of the fingers 240 move beyond the portion of the curved outer surface 122 c with the largest diameter between the proximal and distal ends 122 a and 122 b, the fingers 240 “snap” back to their original shape, thus releasably retaining the head 120 of the bone anchor within the collet 232 via a snap fit. The spherical inner surface of the socket 220 d is sufficiently sized to accommodate snapping the collet 232 into place over the head 120 of the bone anchor 116, and for removal of the bone anchor 116 from the collet 232, while the collet 232 and the bone anchor 116 are disposed within the anchor cartridge 212.

The locking assembly 500 can further include a locking cap 138 and an intermediate wedge 244 that retain the collet 232 in the aperture 222 of the anchor cartridge 212. The intermediate wedge 244 may be disposed within the aperture 222 of the anchor cartridge 212 at a location between the collet 232 and the locking cap 138. The intermediate wedge 244 includes a generally cylindrical shaped body 246 defining an upper surface 246 a at the proximal end of the body 246 and an opposing lower surface 246 b at the distal end of the body 246. The body 246 further includes a raised collar 248 extending upwardly from the center of the upper surface 246 a at the proximal end of the body 246. The collar 248 is configured to be received within the longitudinal aperture 140 d of the locking cap 138. A longitudinal aperture 250 may be formed through the raised collar 248 and the body 246, the diameter of the aperture 250 sufficiently large to allow a guide wire to pass through. The intermediate wedge 244 includes a pair of tabs 252 that extend downward in a distal direction from the lower surface 246 b of the body 246. The tabs 252 are configured to engage the notches 236 of the collet 232. The intermediate wedge 244 can define a radial aperture 254 formed in the wedge body 246 at a location between the upper and lower surfaces 246 a and 246 b.

The locking assembly 500 further includes a peg 256 that can be inserted into the slot 220 f formed in the anchor cartridge 212 and received in the radial aperture 254 when the collet 232 and the intermediate wedge 244 are disposed in the aperture 222 and engaged with each other, so as to prevent axial rotation of the collet 232 and the intermediate wedge 244 within the aperture 222. The peg 256 can be configured such that tip of the peg 256 protrudes from the slot 220 f when the peg 256 is seated within the radial aperture 254, such that when the anchor cartridge 212 is inserted into the bore 210 of the anchor receptacle 208, the tip of the peg is slidably engaged within a longitudinal groove 257 defined in the bore 210 and extending upwardly in a proximal direction from the distal end 208 b of the anchor receptacle 208. When the tip of the peg 256 is disposed within the longitudinal groove 257, axial rotation of the anchor cartridge 212, and thus the collet 232 and the intermediate wedge 244, with respect to the bore 210 is prevented. Additionally, the peg 256 can be configured to limit axial translation of the collet 232 and the intermediate wedge 244 within the anchor receptacle 212 when the peg is disposed in the slot 220 f and received in the radial aperture 254, as illustrated in FIG. 14.

It should be noted that the locking assembly 400 described above with reference to the blade type patient-mounted retractor 102, in particular the collets 128, 154, and 156, and the intermediate wedge 144, may be disposed within the aperture 222 of the anchor cartridge 212, in lieu of the collet 232 and the intermediary wedge 244. Similarly, it should be noted that the locking assembly 500 described above with reference to the tube type patient-mounted retractor 202, in particular the collet 232 and the intermediate wedge 244, may be disposed within the aperture 108 of the anchor receptacle 106 in lieu of the collets 128, 154, and 156, and the intermediate wedge 144.

In an example method of using the tube type patient-mounted retractor 202, the mounting post 115, for example the bone anchor 116, is inserted into the target location 109 of a patient. A tube type retractor 202 may then be connected to the head 120 of the bone anchor 116. The anchor receptacle 208 can be disposed at the distal end 204 b of the body 204. The anchor receptacle 208 may include the anchor cartridge 212 carried in the bore 210. The anchor cartridge 212 may retain the components of the locking assembly 500. To aide deployment of the tube type patient-mounted retractor 202, it may be desirable to first locate a desired insertion point for the bone anchor via the insertion of a guide wire. A cannulated version of the bone anchor 116 may then be inserted into the surgical site over the guide wire to guide the trajectory of the bone anchor as it is driven into place. The guide wire may also be passed through the anchor cartridge 212 and the locking components therein, and used to guide the alignment of the collet with the head of the bone anchor.

The retractor 202 may be connected to the bone anchor 116 by snapping the collet 232 that is disposed in the anchor cartridge 212 over the head 120 of the bone anchor 116. When the retractor body 204 is connected to the head 120 of the bone anchor 116, the retractor 202 is rotatably positionable about the head 120 of the bone anchor 116. The retractor 202 is also axially translatable on the anchor cartridge 212. The retractor 202 may be moved closer to the underlying anatomy at the surgical site, for instance the target location 109, by applying a downward force to the retractor body 204, causing the anchor cartridge 212 to advance within the bore 210. The anchor cartridge 212 may be backed out of the bore 210 by applying a downward force, for example by an instrument inserted into access channel 208 d, on the release tab 230 d, causing the arm 230 of the pawl 226, and thus the engagement member 230 c, to deflect away from the anchor cartridge 212 and to disengage from the annular rings 224. The retractor 202 can then be backed out of the bore 210, or translated away from the target location 109 by lifting up on the retractor body 204. When positioning the retractor 202 within the surgical site at the target location 109, one or more dilators configured for use with the retractor 202 may be used to initially retract patient anatomy from the surgical site.

Referring now to FIGS. 16-18 in particular, once the tube type retractor 202 has been positioned to provide the desired access portal into the surgical site, the retractor body 202 may be positionally fixed with respect to the bone anchor 116 by activating the locking assembly 500 to a locked configuration. In one example, a driving instrument may be inserted into the access channel 208 c of the retractor 202, and a rotational driving force can be applied to the locking cap 138, thereby advancing the locking 138 cap in a distal, or downward, direction within the anchor cartridge 212, toward the collet 232. The advancing locking cap 138 transfers downward force to the intermediate wedge 244, causing the intermediate wedge 244 to be advanced in a downward direction within the anchor receptacle 212. As the intermediate wedge 244 advances downward, the tabs 252 of the intermediate wedge 244 engage the slots 236 of the collet 232, transferring downward force from the intermediate wedge 244 to the collet 232, thereby causing the retention fingers 240 to interfere with the inner surface of the socket 220 d at the distal end 220 b of the anchor cartridge 212, and to collapse around the head 120 of the bone anchor 116, thereby fixing the anchor receptacle, and thus the retractor body 204, in position with respect to the head 120 of the bone anchor 116 via a crush lock between the collet 232 and the bone anchor 116.

If a surgeon performing a procedure desires to reposition the tube type patient-mounted retractor 202 during a procedure, a rotational driving force of the opposite direction to that applied during activation of the locking assembly 500 may be applied to release the locking assembly 500 to an unlocked configuration, thereby allowing the retractor 202 to be polyaxially positionable with respect to the bone anchor 116. The retractor 202 can further be axially translated with respect to the anchor cartridge 212 by applying a downward force to the release tab 230 d of the pawl 226. When the retractor 202 is repositioned as desired, the locking assembly 500 can be activated again to its locked configuration as described above to re-lock the retractor body 204 in position with respect to the head 120 of the bone anchor 116. The tube type patient-mounted retractor 202 can be removed from the surgical site by releasing the locking assembly 500 and applying an upward force to the retractor body 204, thereby causing the collet 232 to disengage from the head 120 of the bone anchor 116. The bone anchor 116 may then be removed from the surgical site, or may be re-used, for example as a bone anchoring element of a bottom-loading pedicle screw assembly. It should be noted that while the instant example method is discussed within reference to the tube type patient-mounted retractor 202, it is possible to use blade type patient-mounted retractors 102 in combination with tube type patient-mounted retractors 202 during a single procedure. For example, if a procedure calls for incisions into multiple target locations 107 and/or 109, one or more blade type retractors 102 may be disposed at the target location 107, while a tube type retractor 202 may be disposed at the target location 209.

It should be appreciated that a variety of kits, for example surgical kits assembled for particular procedures, can be provided that include one or more components of the patient mounted retractor assemblies 100, 200 and systems disclosed herein. The components of the kits may be configured the same or differently. For example, within a single kit, a variety of blade type patient-mounted retractors 102 may be provided that have different retractor body geometries, different materials of manufacture, different locking assembly components or none at all, may or may not include an anchor receptacle, may or may not have a bore within the anchor receptacle for receiving an anchor cartridge, may or may not have one or more flanges formed thereon, may or may not have tabs formed at the distal ends of the flanges, may or may not have one or more sections of flexible skirting affixed to the distal ends of the flanges, etc., depending, for example, on the type of procedure being performed by a surgeon, on the particular surgical site location within a patient, on the size and/or anatomy of a patient, and the like. Alternatively, a kit may be configured with a plurality of identical blade type patient-mounted retractors 102. Within another single kit, a variety of tube type patient-mounted retractors 202 may be provided that have different retractor body geometries and/or different bore geometries, different heights, different materials of manufacture, different locking assembly components or none at all, may or may not include an anchor receptacle, may or may not have a bore within the anchor receptacle for receiving an anchor cartridge, may or may not have tabs formed at the distal ends of the retractor bodies, may or may not have one or more sections of flexible skirting affixed to the distal ends of the retractor bodies, etc., depending, for example, on the type of procedure being performed by a surgeon, on the particular surgical site location within a patient, on the size and/or anatomy of a patient, and the like. Alternatively, a kit may be configured with a plurality of identical tube type patient-mounted retractors 102.

The kits may also be configured differently with respect to which components of the individual patient-mounted retractor assemblies 100, 200 are included in the kits. For example, a single kit may include one or more blade and tube type patient-mounted retractors of various configurations and/or geometries, various locking assembly components, mounting posts of various types, for example bone anchors of varying lengths with polyaxial heads, dilators, guide wires of various lengths and/or diameters, and the like. Example kits may also include driving instruments.

Although blade and tube type patient-mounted retractors have been described herein with reference to preferred embodiments or preferred methods, it should be understood that the words which have been used herein are words of description and illustration, rather than words of limitation. For example, it should be appreciated that the various structure, features, and methods described above with respect to the blade type patient-mounted retractors may be combined with or otherwise integrated with the various structure, features, and methods described above with respect to the tube type patient-mounted retractors, and that similarly the various structure, features, and methods described above with respect to the tube type patient-mounted retractors may be combined with or otherwise integrated with the various structure, features, and methods described above with respect to the blade type patient-mounted retractors. Furthermore, it should be noted that although the blade and tube type patient-mounted retractors have been described herein with reference to particular structure, methods, and/or embodiments, the scope of the instant disclosure is not intended to be limited to those particulars, but rather is meant to extend to all structures, methods, and/or uses of blade and/or tube type patient-mounted retractors. Those skilled in the relevant art, having the benefit of the teachings of this specification, may effect numerous modifications to the blade and/or tube type patient mounted retractors and their corresponding assemblies as described herein, and changes may be made without departing from the scope and spirit of the instant disclosure, for instance as recited in the appended claims. 

What is claimed:
 1. A retractor assembly comprising: a retractor body including a proximal end defined along a first axis and a distal end opposite the proximal end, the proximal end defining an inner surface that faces the first axis, and an outer surface opposed to the inner surface, wherein at least a portion of the retractor body is open so as to define a channel, the channel being elongate along the first axis, the first axis extending through the channel; an anchor receptacle disposed at the distal end of the retractor body, the anchor receptacle defined along a second axis that extends through the channel, the anchor receptacle having an anchor receptacle proximal end and an anchor receptacle distal end that is spaced from the anchor receptacle proximal end along the second axis, wherein the channel is open from the proximal end of the retractor body toward the anchor receptacle proximal end, wherein the second axis is offset with respect to the first axis such that 1) an entirety of the proximal end of the retractor body is offset from the second axis in a direction that is perpendicular to the second axis, and 2) the outer surface of the proximal end of the retractor body faces the second axis; and a locking assembly carried by the anchor receptacle, the locking assembly configured to attach to the retractor body and to a bone anchor that is configured to be driven into an underlying target location of a patient such that the bone anchor is connectable to the retractor body, wherein the second axis extends through the locking assembly.
 2. The retractor assembly of claim 1, wherein the locking assembly comprises: a collet having a proximal end, a distal end opposite the proximal end, and an interior volume defined within the distal end, the interior volume configured to capture and retain a head of the bone anchor; and a locking cap having a threaded outer surface configured to engage complimentary threads formed within the anchor receptacle, wherein the retractor assembly is configured such that application of a rotational force to the locking cap advances the locking cap within the anchor receptacle, thereby causing the collet to create an interference force between the head of the bone anchor and the anchor receptacle, thereby locking a position of the retractor body relative to the bone anchor.
 3. The retractor assembly of claim 2, wherein the collet has a plurality of slots formed in the distal end, the slots defining a plurality of deflectable fingers.
 4. The retractor assembly of claim 2, wherein the proximal end of the collet has an upper surface with an engagement structure formed thereon, the engagement structure configured to engage a lower surface of the locking cap.
 5. The retractor assembly of claim 2, further comprising a wedge disposed between the collet and the locking cap, the wedge configured to distribute force from the locking cap to the collet when the locking cap is advanced within the anchor receptacle.
 6. The retractor assembly of claim 1, the retractor body further defining an intermediate portion that is open and extends between the proximal and distal ends along a third axis that is offset with respect to the first and second axes, wherein the channel surrounds the first, second, and third axes.
 7. The retractor assembly of claim 6, wherein the intermediate portion defines at least a portion of the channel.
 8. The retractor assembly of claim 7, wherein the intermediate portion of the retractor body has an aperture formed therethrough, the aperture configured to receive a driving instrument.
 9. The retractor assembly of claim 6, wherein a cross sectional dimension of the intermediate portion varies in magnitude between the proximal and distal ends.
 10. The retractor assembly of claim 6, wherein the intermediate portion is defined along the third axis that is offset with respect to the first and second axes, respectively, and wherein the intermediate portion defines an offset region between the proximal and distal ends.
 11. The retractor assembly of claim 1, wherein the first and second axes are substantially parallel with respect to each other.
 12. A retractor assembly configured to be attached to a bone anchor, the retractor assembly comprising: a retractor body defining a proximal end and a distal end spaced from the proximal end in a distal direction, the retractor body defining a first axis oriented along the distal direction, the retractor body further defining a mounting member formed at the distal end, the mounting member centrally disposed along a second axis that is offset with respect to the first axis, the mounting member defining a bore that extends along the second axis, the bore defining an inner surface; a pawl comprising a tooth configured to extend radially inward from the inner surface of the bore toward the second axis; and a locking assembly configured to be attached to the bone anchor, the locking assembly comprising an anchor cartridge that is configured to receive a head of the bone anchor, the anchor cartridge further configured to translate within the bore along the second axis, the anchor cartridge having an outer surface with a plurality of annular ridges formed thereon, the annular ridges configured to releasably engage with the pawl so as to retain the anchor cartridge within the bore, wherein the tooth is configured to interlock with at least one of the annular ridges so as to prevent the anchor cartridge from translating in the distal direction relative to the retractor body, and the pawl includes a release member that is configured to pivot the pawl so as to disengage the tooth from the at least one of the annular ridges, wherein, when the tooth is disengaged, the anchor cartridge is translatable in the distal direction relative to the retractor body.
 13. The retractor assembly of claim 12, wherein the locking assembly further comprises a collet having a proximal end, a distal end opposite the proximal end, and an interior volume defined within the distal end of the collet, the interior volume configured to capture and retain the head of the bone anchor, wherein the collet is configured to create an interference force between the head of the bone anchor and the anchor cartridge.
 14. The retractor assembly of claim 13, wherein: the anchor cartridge comprises internal threads; and the locking assembly further comprises a locking cap having a threaded outer surface configured to engage the internal threads such that application of a rotational force to the locking cap advances the locking cap within the anchor cartridge, thereby causing the collet to create the interference force between the head of the bone anchor and the anchor cartridge, thereby locking a position of the retractor body relative to the bone anchor.
 15. The retractor assembly of claim 12, wherein the retractor body defines a channel that defines at least a portion of an access portal in the patient.
 16. The retractor assembly of claim 15, wherein the channel is open from the proximal end of the retractor body toward the mounting member.
 17. The retractor assembly of claim 15, wherein the retractor body includes a cannulation between the proximal and distal ends of the retractor body, the cannulation defining the channel.
 18. The retractor assembly of claim 12, wherein the locking assembly is configured such that when the locking assembly is attached onto the bone anchor, the locking assembly can iterate between an unlocked configuration defined as when the retractor body is rotatable with respect to the bone anchor, and a locked configuration defined as when the retractor body is not rotatable with respect the bone anchor. 